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TOMOYO Linux Cross Reference
Linux/net/can/bcm.c

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  1 /*
  2  * bcm.c - Broadcast Manager to filter/send (cyclic) CAN content
  3  *
  4  * Copyright (c) 2002-2007 Volkswagen Group Electronic Research
  5  * All rights reserved.
  6  *
  7  * Redistribution and use in source and binary forms, with or without
  8  * modification, are permitted provided that the following conditions
  9  * are met:
 10  * 1. Redistributions of source code must retain the above copyright
 11  *    notice, this list of conditions and the following disclaimer.
 12  * 2. Redistributions in binary form must reproduce the above copyright
 13  *    notice, this list of conditions and the following disclaimer in the
 14  *    documentation and/or other materials provided with the distribution.
 15  * 3. Neither the name of Volkswagen nor the names of its contributors
 16  *    may be used to endorse or promote products derived from this software
 17  *    without specific prior written permission.
 18  *
 19  * Alternatively, provided that this notice is retained in full, this
 20  * software may be distributed under the terms of the GNU General
 21  * Public License ("GPL") version 2, in which case the provisions of the
 22  * GPL apply INSTEAD OF those given above.
 23  *
 24  * The provided data structures and external interfaces from this code
 25  * are not restricted to be used by modules with a GPL compatible license.
 26  *
 27  * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
 28  * "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
 29  * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
 30  * A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
 31  * OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
 32  * SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
 33  * LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
 34  * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
 35  * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
 36  * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
 37  * OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH
 38  * DAMAGE.
 39  *
 40  */
 41 
 42 #include <linux/module.h>
 43 #include <linux/init.h>
 44 #include <linux/interrupt.h>
 45 #include <linux/hrtimer.h>
 46 #include <linux/list.h>
 47 #include <linux/proc_fs.h>
 48 #include <linux/seq_file.h>
 49 #include <linux/uio.h>
 50 #include <linux/net.h>
 51 #include <linux/netdevice.h>
 52 #include <linux/socket.h>
 53 #include <linux/if_arp.h>
 54 #include <linux/skbuff.h>
 55 #include <linux/can.h>
 56 #include <linux/can/core.h>
 57 #include <linux/can/skb.h>
 58 #include <linux/can/bcm.h>
 59 #include <linux/slab.h>
 60 #include <net/sock.h>
 61 #include <net/net_namespace.h>
 62 
 63 /*
 64  * To send multiple CAN frame content within TX_SETUP or to filter
 65  * CAN messages with multiplex index within RX_SETUP, the number of
 66  * different filters is limited to 256 due to the one byte index value.
 67  */
 68 #define MAX_NFRAMES 256
 69 
 70 /* use of last_frames[index].can_dlc */
 71 #define RX_RECV    0x40 /* received data for this element */
 72 #define RX_THR     0x80 /* element not been sent due to throttle feature */
 73 #define BCM_CAN_DLC_MASK 0x0F /* clean private flags in can_dlc by masking */
 74 
 75 /* get best masking value for can_rx_register() for a given single can_id */
 76 #define REGMASK(id) ((id & CAN_EFF_FLAG) ? \
 77                      (CAN_EFF_MASK | CAN_EFF_FLAG | CAN_RTR_FLAG) : \
 78                      (CAN_SFF_MASK | CAN_EFF_FLAG | CAN_RTR_FLAG))
 79 
 80 #define CAN_BCM_VERSION CAN_VERSION
 81 static __initconst const char banner[] = KERN_INFO
 82         "can: broadcast manager protocol (rev " CAN_BCM_VERSION " t)\n";
 83 
 84 MODULE_DESCRIPTION("PF_CAN broadcast manager protocol");
 85 MODULE_LICENSE("Dual BSD/GPL");
 86 MODULE_AUTHOR("Oliver Hartkopp <oliver.hartkopp@volkswagen.de>");
 87 MODULE_ALIAS("can-proto-2");
 88 
 89 /* easy access to can_frame payload */
 90 static inline u64 GET_U64(const struct can_frame *cp)
 91 {
 92         return *(u64 *)cp->data;
 93 }
 94 
 95 struct bcm_op {
 96         struct list_head list;
 97         int ifindex;
 98         canid_t can_id;
 99         u32 flags;
100         unsigned long frames_abs, frames_filtered;
101         struct timeval ival1, ival2;
102         struct hrtimer timer, thrtimer;
103         struct tasklet_struct tsklet, thrtsklet;
104         ktime_t rx_stamp, kt_ival1, kt_ival2, kt_lastmsg;
105         int rx_ifindex;
106         u32 count;
107         u32 nframes;
108         u32 currframe;
109         struct can_frame *frames;
110         struct can_frame *last_frames;
111         struct can_frame sframe;
112         struct can_frame last_sframe;
113         struct sock *sk;
114         struct net_device *rx_reg_dev;
115 };
116 
117 static struct proc_dir_entry *proc_dir;
118 
119 struct bcm_sock {
120         struct sock sk;
121         int bound;
122         int ifindex;
123         struct notifier_block notifier;
124         struct list_head rx_ops;
125         struct list_head tx_ops;
126         unsigned long dropped_usr_msgs;
127         struct proc_dir_entry *bcm_proc_read;
128         char procname [32]; /* inode number in decimal with \0 */
129 };
130 
131 static inline struct bcm_sock *bcm_sk(const struct sock *sk)
132 {
133         return (struct bcm_sock *)sk;
134 }
135 
136 #define CFSIZ sizeof(struct can_frame)
137 #define OPSIZ sizeof(struct bcm_op)
138 #define MHSIZ sizeof(struct bcm_msg_head)
139 
140 /*
141  * procfs functions
142  */
143 static char *bcm_proc_getifname(char *result, int ifindex)
144 {
145         struct net_device *dev;
146 
147         if (!ifindex)
148                 return "any";
149 
150         rcu_read_lock();
151         dev = dev_get_by_index_rcu(&init_net, ifindex);
152         if (dev)
153                 strcpy(result, dev->name);
154         else
155                 strcpy(result, "???");
156         rcu_read_unlock();
157 
158         return result;
159 }
160 
161 static int bcm_proc_show(struct seq_file *m, void *v)
162 {
163         char ifname[IFNAMSIZ];
164         struct sock *sk = (struct sock *)m->private;
165         struct bcm_sock *bo = bcm_sk(sk);
166         struct bcm_op *op;
167 
168         seq_printf(m, ">>> socket %pK", sk->sk_socket);
169         seq_printf(m, " / sk %pK", sk);
170         seq_printf(m, " / bo %pK", bo);
171         seq_printf(m, " / dropped %lu", bo->dropped_usr_msgs);
172         seq_printf(m, " / bound %s", bcm_proc_getifname(ifname, bo->ifindex));
173         seq_printf(m, " <<<\n");
174 
175         list_for_each_entry(op, &bo->rx_ops, list) {
176 
177                 unsigned long reduction;
178 
179                 /* print only active entries & prevent division by zero */
180                 if (!op->frames_abs)
181                         continue;
182 
183                 seq_printf(m, "rx_op: %03X %-5s ",
184                                 op->can_id, bcm_proc_getifname(ifname, op->ifindex));
185                 seq_printf(m, "[%u]%c ", op->nframes,
186                                 (op->flags & RX_CHECK_DLC)?'d':' ');
187                 if (op->kt_ival1.tv64)
188                         seq_printf(m, "timeo=%lld ",
189                                         (long long)
190                                         ktime_to_us(op->kt_ival1));
191 
192                 if (op->kt_ival2.tv64)
193                         seq_printf(m, "thr=%lld ",
194                                         (long long)
195                                         ktime_to_us(op->kt_ival2));
196 
197                 seq_printf(m, "# recv %ld (%ld) => reduction: ",
198                                 op->frames_filtered, op->frames_abs);
199 
200                 reduction = 100 - (op->frames_filtered * 100) / op->frames_abs;
201 
202                 seq_printf(m, "%s%ld%%\n",
203                                 (reduction == 100)?"near ":"", reduction);
204         }
205 
206         list_for_each_entry(op, &bo->tx_ops, list) {
207 
208                 seq_printf(m, "tx_op: %03X %s [%u] ",
209                                 op->can_id,
210                                 bcm_proc_getifname(ifname, op->ifindex),
211                                 op->nframes);
212 
213                 if (op->kt_ival1.tv64)
214                         seq_printf(m, "t1=%lld ",
215                                         (long long) ktime_to_us(op->kt_ival1));
216 
217                 if (op->kt_ival2.tv64)
218                         seq_printf(m, "t2=%lld ",
219                                         (long long) ktime_to_us(op->kt_ival2));
220 
221                 seq_printf(m, "# sent %ld\n", op->frames_abs);
222         }
223         seq_putc(m, '\n');
224         return 0;
225 }
226 
227 static int bcm_proc_open(struct inode *inode, struct file *file)
228 {
229         return single_open(file, bcm_proc_show, PDE_DATA(inode));
230 }
231 
232 static const struct file_operations bcm_proc_fops = {
233         .owner          = THIS_MODULE,
234         .open           = bcm_proc_open,
235         .read           = seq_read,
236         .llseek         = seq_lseek,
237         .release        = single_release,
238 };
239 
240 /*
241  * bcm_can_tx - send the (next) CAN frame to the appropriate CAN interface
242  *              of the given bcm tx op
243  */
244 static void bcm_can_tx(struct bcm_op *op)
245 {
246         struct sk_buff *skb;
247         struct net_device *dev;
248         struct can_frame *cf = &op->frames[op->currframe];
249 
250         /* no target device? => exit */
251         if (!op->ifindex)
252                 return;
253 
254         dev = dev_get_by_index(&init_net, op->ifindex);
255         if (!dev) {
256                 /* RFC: should this bcm_op remove itself here? */
257                 return;
258         }
259 
260         skb = alloc_skb(CFSIZ + sizeof(struct can_skb_priv), gfp_any());
261         if (!skb)
262                 goto out;
263 
264         can_skb_reserve(skb);
265         can_skb_prv(skb)->ifindex = dev->ifindex;
266 
267         memcpy(skb_put(skb, CFSIZ), cf, CFSIZ);
268 
269         /* send with loopback */
270         skb->dev = dev;
271         can_skb_set_owner(skb, op->sk);
272         can_send(skb, 1);
273 
274         /* update statistics */
275         op->currframe++;
276         op->frames_abs++;
277 
278         /* reached last frame? */
279         if (op->currframe >= op->nframes)
280                 op->currframe = 0;
281  out:
282         dev_put(dev);
283 }
284 
285 /*
286  * bcm_send_to_user - send a BCM message to the userspace
287  *                    (consisting of bcm_msg_head + x CAN frames)
288  */
289 static void bcm_send_to_user(struct bcm_op *op, struct bcm_msg_head *head,
290                              struct can_frame *frames, int has_timestamp)
291 {
292         struct sk_buff *skb;
293         struct can_frame *firstframe;
294         struct sockaddr_can *addr;
295         struct sock *sk = op->sk;
296         unsigned int datalen = head->nframes * CFSIZ;
297         int err;
298 
299         skb = alloc_skb(sizeof(*head) + datalen, gfp_any());
300         if (!skb)
301                 return;
302 
303         memcpy(skb_put(skb, sizeof(*head)), head, sizeof(*head));
304 
305         if (head->nframes) {
306                 /* can_frames starting here */
307                 firstframe = (struct can_frame *)skb_tail_pointer(skb);
308 
309                 memcpy(skb_put(skb, datalen), frames, datalen);
310 
311                 /*
312                  * the BCM uses the can_dlc-element of the can_frame
313                  * structure for internal purposes. This is only
314                  * relevant for updates that are generated by the
315                  * BCM, where nframes is 1
316                  */
317                 if (head->nframes == 1)
318                         firstframe->can_dlc &= BCM_CAN_DLC_MASK;
319         }
320 
321         if (has_timestamp) {
322                 /* restore rx timestamp */
323                 skb->tstamp = op->rx_stamp;
324         }
325 
326         /*
327          *  Put the datagram to the queue so that bcm_recvmsg() can
328          *  get it from there.  We need to pass the interface index to
329          *  bcm_recvmsg().  We pass a whole struct sockaddr_can in skb->cb
330          *  containing the interface index.
331          */
332 
333         BUILD_BUG_ON(sizeof(skb->cb) < sizeof(struct sockaddr_can));
334         addr = (struct sockaddr_can *)skb->cb;
335         memset(addr, 0, sizeof(*addr));
336         addr->can_family  = AF_CAN;
337         addr->can_ifindex = op->rx_ifindex;
338 
339         err = sock_queue_rcv_skb(sk, skb);
340         if (err < 0) {
341                 struct bcm_sock *bo = bcm_sk(sk);
342 
343                 kfree_skb(skb);
344                 /* don't care about overflows in this statistic */
345                 bo->dropped_usr_msgs++;
346         }
347 }
348 
349 static void bcm_tx_start_timer(struct bcm_op *op)
350 {
351         if (op->kt_ival1.tv64 && op->count)
352                 hrtimer_start(&op->timer,
353                               ktime_add(ktime_get(), op->kt_ival1),
354                               HRTIMER_MODE_ABS);
355         else if (op->kt_ival2.tv64)
356                 hrtimer_start(&op->timer,
357                               ktime_add(ktime_get(), op->kt_ival2),
358                               HRTIMER_MODE_ABS);
359 }
360 
361 static void bcm_tx_timeout_tsklet(unsigned long data)
362 {
363         struct bcm_op *op = (struct bcm_op *)data;
364         struct bcm_msg_head msg_head;
365 
366         if (op->kt_ival1.tv64 && (op->count > 0)) {
367 
368                 op->count--;
369                 if (!op->count && (op->flags & TX_COUNTEVT)) {
370 
371                         /* create notification to user */
372                         msg_head.opcode  = TX_EXPIRED;
373                         msg_head.flags   = op->flags;
374                         msg_head.count   = op->count;
375                         msg_head.ival1   = op->ival1;
376                         msg_head.ival2   = op->ival2;
377                         msg_head.can_id  = op->can_id;
378                         msg_head.nframes = 0;
379 
380                         bcm_send_to_user(op, &msg_head, NULL, 0);
381                 }
382                 bcm_can_tx(op);
383 
384         } else if (op->kt_ival2.tv64)
385                 bcm_can_tx(op);
386 
387         bcm_tx_start_timer(op);
388 }
389 
390 /*
391  * bcm_tx_timeout_handler - performs cyclic CAN frame transmissions
392  */
393 static enum hrtimer_restart bcm_tx_timeout_handler(struct hrtimer *hrtimer)
394 {
395         struct bcm_op *op = container_of(hrtimer, struct bcm_op, timer);
396 
397         tasklet_schedule(&op->tsklet);
398 
399         return HRTIMER_NORESTART;
400 }
401 
402 /*
403  * bcm_rx_changed - create a RX_CHANGED notification due to changed content
404  */
405 static void bcm_rx_changed(struct bcm_op *op, struct can_frame *data)
406 {
407         struct bcm_msg_head head;
408 
409         /* update statistics */
410         op->frames_filtered++;
411 
412         /* prevent statistics overflow */
413         if (op->frames_filtered > ULONG_MAX/100)
414                 op->frames_filtered = op->frames_abs = 0;
415 
416         /* this element is not throttled anymore */
417         data->can_dlc &= (BCM_CAN_DLC_MASK|RX_RECV);
418 
419         head.opcode  = RX_CHANGED;
420         head.flags   = op->flags;
421         head.count   = op->count;
422         head.ival1   = op->ival1;
423         head.ival2   = op->ival2;
424         head.can_id  = op->can_id;
425         head.nframes = 1;
426 
427         bcm_send_to_user(op, &head, data, 1);
428 }
429 
430 /*
431  * bcm_rx_update_and_send - process a detected relevant receive content change
432  *                          1. update the last received data
433  *                          2. send a notification to the user (if possible)
434  */
435 static void bcm_rx_update_and_send(struct bcm_op *op,
436                                    struct can_frame *lastdata,
437                                    const struct can_frame *rxdata)
438 {
439         memcpy(lastdata, rxdata, CFSIZ);
440 
441         /* mark as used and throttled by default */
442         lastdata->can_dlc |= (RX_RECV|RX_THR);
443 
444         /* throtteling mode inactive ? */
445         if (!op->kt_ival2.tv64) {
446                 /* send RX_CHANGED to the user immediately */
447                 bcm_rx_changed(op, lastdata);
448                 return;
449         }
450 
451         /* with active throttling timer we are just done here */
452         if (hrtimer_active(&op->thrtimer))
453                 return;
454 
455         /* first receiption with enabled throttling mode */
456         if (!op->kt_lastmsg.tv64)
457                 goto rx_changed_settime;
458 
459         /* got a second frame inside a potential throttle period? */
460         if (ktime_us_delta(ktime_get(), op->kt_lastmsg) <
461             ktime_to_us(op->kt_ival2)) {
462                 /* do not send the saved data - only start throttle timer */
463                 hrtimer_start(&op->thrtimer,
464                               ktime_add(op->kt_lastmsg, op->kt_ival2),
465                               HRTIMER_MODE_ABS);
466                 return;
467         }
468 
469         /* the gap was that big, that throttling was not needed here */
470 rx_changed_settime:
471         bcm_rx_changed(op, lastdata);
472         op->kt_lastmsg = ktime_get();
473 }
474 
475 /*
476  * bcm_rx_cmp_to_index - (bit)compares the currently received data to formerly
477  *                       received data stored in op->last_frames[]
478  */
479 static void bcm_rx_cmp_to_index(struct bcm_op *op, unsigned int index,
480                                 const struct can_frame *rxdata)
481 {
482         /*
483          * no one uses the MSBs of can_dlc for comparation,
484          * so we use it here to detect the first time of reception
485          */
486 
487         if (!(op->last_frames[index].can_dlc & RX_RECV)) {
488                 /* received data for the first time => send update to user */
489                 bcm_rx_update_and_send(op, &op->last_frames[index], rxdata);
490                 return;
491         }
492 
493         /* do a real check in can_frame data section */
494 
495         if ((GET_U64(&op->frames[index]) & GET_U64(rxdata)) !=
496             (GET_U64(&op->frames[index]) & GET_U64(&op->last_frames[index]))) {
497                 bcm_rx_update_and_send(op, &op->last_frames[index], rxdata);
498                 return;
499         }
500 
501         if (op->flags & RX_CHECK_DLC) {
502                 /* do a real check in can_frame dlc */
503                 if (rxdata->can_dlc != (op->last_frames[index].can_dlc &
504                                         BCM_CAN_DLC_MASK)) {
505                         bcm_rx_update_and_send(op, &op->last_frames[index],
506                                                rxdata);
507                         return;
508                 }
509         }
510 }
511 
512 /*
513  * bcm_rx_starttimer - enable timeout monitoring for CAN frame receiption
514  */
515 static void bcm_rx_starttimer(struct bcm_op *op)
516 {
517         if (op->flags & RX_NO_AUTOTIMER)
518                 return;
519 
520         if (op->kt_ival1.tv64)
521                 hrtimer_start(&op->timer, op->kt_ival1, HRTIMER_MODE_REL);
522 }
523 
524 static void bcm_rx_timeout_tsklet(unsigned long data)
525 {
526         struct bcm_op *op = (struct bcm_op *)data;
527         struct bcm_msg_head msg_head;
528 
529         /* create notification to user */
530         msg_head.opcode  = RX_TIMEOUT;
531         msg_head.flags   = op->flags;
532         msg_head.count   = op->count;
533         msg_head.ival1   = op->ival1;
534         msg_head.ival2   = op->ival2;
535         msg_head.can_id  = op->can_id;
536         msg_head.nframes = 0;
537 
538         bcm_send_to_user(op, &msg_head, NULL, 0);
539 }
540 
541 /*
542  * bcm_rx_timeout_handler - when the (cyclic) CAN frame receiption timed out
543  */
544 static enum hrtimer_restart bcm_rx_timeout_handler(struct hrtimer *hrtimer)
545 {
546         struct bcm_op *op = container_of(hrtimer, struct bcm_op, timer);
547 
548         /* schedule before NET_RX_SOFTIRQ */
549         tasklet_hi_schedule(&op->tsklet);
550 
551         /* no restart of the timer is done here! */
552 
553         /* if user wants to be informed, when cyclic CAN-Messages come back */
554         if ((op->flags & RX_ANNOUNCE_RESUME) && op->last_frames) {
555                 /* clear received can_frames to indicate 'nothing received' */
556                 memset(op->last_frames, 0, op->nframes * CFSIZ);
557         }
558 
559         return HRTIMER_NORESTART;
560 }
561 
562 /*
563  * bcm_rx_do_flush - helper for bcm_rx_thr_flush
564  */
565 static inline int bcm_rx_do_flush(struct bcm_op *op, int update,
566                                   unsigned int index)
567 {
568         if ((op->last_frames) && (op->last_frames[index].can_dlc & RX_THR)) {
569                 if (update)
570                         bcm_rx_changed(op, &op->last_frames[index]);
571                 return 1;
572         }
573         return 0;
574 }
575 
576 /*
577  * bcm_rx_thr_flush - Check for throttled data and send it to the userspace
578  *
579  * update == 0 : just check if throttled data is available  (any irq context)
580  * update == 1 : check and send throttled data to userspace (soft_irq context)
581  */
582 static int bcm_rx_thr_flush(struct bcm_op *op, int update)
583 {
584         int updated = 0;
585 
586         if (op->nframes > 1) {
587                 unsigned int i;
588 
589                 /* for MUX filter we start at index 1 */
590                 for (i = 1; i < op->nframes; i++)
591                         updated += bcm_rx_do_flush(op, update, i);
592 
593         } else {
594                 /* for RX_FILTER_ID and simple filter */
595                 updated += bcm_rx_do_flush(op, update, 0);
596         }
597 
598         return updated;
599 }
600 
601 static void bcm_rx_thr_tsklet(unsigned long data)
602 {
603         struct bcm_op *op = (struct bcm_op *)data;
604 
605         /* push the changed data to the userspace */
606         bcm_rx_thr_flush(op, 1);
607 }
608 
609 /*
610  * bcm_rx_thr_handler - the time for blocked content updates is over now:
611  *                      Check for throttled data and send it to the userspace
612  */
613 static enum hrtimer_restart bcm_rx_thr_handler(struct hrtimer *hrtimer)
614 {
615         struct bcm_op *op = container_of(hrtimer, struct bcm_op, thrtimer);
616 
617         tasklet_schedule(&op->thrtsklet);
618 
619         if (bcm_rx_thr_flush(op, 0)) {
620                 hrtimer_forward(hrtimer, ktime_get(), op->kt_ival2);
621                 return HRTIMER_RESTART;
622         } else {
623                 /* rearm throttle handling */
624                 op->kt_lastmsg = ktime_set(0, 0);
625                 return HRTIMER_NORESTART;
626         }
627 }
628 
629 /*
630  * bcm_rx_handler - handle a CAN frame receiption
631  */
632 static void bcm_rx_handler(struct sk_buff *skb, void *data)
633 {
634         struct bcm_op *op = (struct bcm_op *)data;
635         const struct can_frame *rxframe = (struct can_frame *)skb->data;
636         unsigned int i;
637 
638         /* disable timeout */
639         hrtimer_cancel(&op->timer);
640 
641         if (op->can_id != rxframe->can_id)
642                 return;
643 
644         /* save rx timestamp */
645         op->rx_stamp = skb->tstamp;
646         /* save originator for recvfrom() */
647         op->rx_ifindex = skb->dev->ifindex;
648         /* update statistics */
649         op->frames_abs++;
650 
651         if (op->flags & RX_RTR_FRAME) {
652                 /* send reply for RTR-request (placed in op->frames[0]) */
653                 bcm_can_tx(op);
654                 return;
655         }
656 
657         if (op->flags & RX_FILTER_ID) {
658                 /* the easiest case */
659                 bcm_rx_update_and_send(op, &op->last_frames[0], rxframe);
660                 goto rx_starttimer;
661         }
662 
663         if (op->nframes == 1) {
664                 /* simple compare with index 0 */
665                 bcm_rx_cmp_to_index(op, 0, rxframe);
666                 goto rx_starttimer;
667         }
668 
669         if (op->nframes > 1) {
670                 /*
671                  * multiplex compare
672                  *
673                  * find the first multiplex mask that fits.
674                  * Remark: The MUX-mask is stored in index 0
675                  */
676 
677                 for (i = 1; i < op->nframes; i++) {
678                         if ((GET_U64(&op->frames[0]) & GET_U64(rxframe)) ==
679                             (GET_U64(&op->frames[0]) &
680                              GET_U64(&op->frames[i]))) {
681                                 bcm_rx_cmp_to_index(op, i, rxframe);
682                                 break;
683                         }
684                 }
685         }
686 
687 rx_starttimer:
688         bcm_rx_starttimer(op);
689 }
690 
691 /*
692  * helpers for bcm_op handling: find & delete bcm [rx|tx] op elements
693  */
694 static struct bcm_op *bcm_find_op(struct list_head *ops, canid_t can_id,
695                                   int ifindex)
696 {
697         struct bcm_op *op;
698 
699         list_for_each_entry(op, ops, list) {
700                 if ((op->can_id == can_id) && (op->ifindex == ifindex))
701                         return op;
702         }
703 
704         return NULL;
705 }
706 
707 static void bcm_remove_op(struct bcm_op *op)
708 {
709         if (op->tsklet.func) {
710                 while (test_bit(TASKLET_STATE_SCHED, &op->tsklet.state) ||
711                        test_bit(TASKLET_STATE_RUN, &op->tsklet.state) ||
712                        hrtimer_active(&op->timer)) {
713                         hrtimer_cancel(&op->timer);
714                         tasklet_kill(&op->tsklet);
715                 }
716         }
717 
718         if (op->thrtsklet.func) {
719                 while (test_bit(TASKLET_STATE_SCHED, &op->thrtsklet.state) ||
720                        test_bit(TASKLET_STATE_RUN, &op->thrtsklet.state) ||
721                        hrtimer_active(&op->thrtimer)) {
722                         hrtimer_cancel(&op->thrtimer);
723                         tasklet_kill(&op->thrtsklet);
724                 }
725         }
726 
727         if ((op->frames) && (op->frames != &op->sframe))
728                 kfree(op->frames);
729 
730         if ((op->last_frames) && (op->last_frames != &op->last_sframe))
731                 kfree(op->last_frames);
732 
733         kfree(op);
734 }
735 
736 static void bcm_rx_unreg(struct net_device *dev, struct bcm_op *op)
737 {
738         if (op->rx_reg_dev == dev) {
739                 can_rx_unregister(dev, op->can_id, REGMASK(op->can_id),
740                                   bcm_rx_handler, op);
741 
742                 /* mark as removed subscription */
743                 op->rx_reg_dev = NULL;
744         } else
745                 printk(KERN_ERR "can-bcm: bcm_rx_unreg: registered device "
746                        "mismatch %p %p\n", op->rx_reg_dev, dev);
747 }
748 
749 /*
750  * bcm_delete_rx_op - find and remove a rx op (returns number of removed ops)
751  */
752 static int bcm_delete_rx_op(struct list_head *ops, canid_t can_id, int ifindex)
753 {
754         struct bcm_op *op, *n;
755 
756         list_for_each_entry_safe(op, n, ops, list) {
757                 if ((op->can_id == can_id) && (op->ifindex == ifindex)) {
758 
759                         /*
760                          * Don't care if we're bound or not (due to netdev
761                          * problems) can_rx_unregister() is always a save
762                          * thing to do here.
763                          */
764                         if (op->ifindex) {
765                                 /*
766                                  * Only remove subscriptions that had not
767                                  * been removed due to NETDEV_UNREGISTER
768                                  * in bcm_notifier()
769                                  */
770                                 if (op->rx_reg_dev) {
771                                         struct net_device *dev;
772 
773                                         dev = dev_get_by_index(&init_net,
774                                                                op->ifindex);
775                                         if (dev) {
776                                                 bcm_rx_unreg(dev, op);
777                                                 dev_put(dev);
778                                         }
779                                 }
780                         } else
781                                 can_rx_unregister(NULL, op->can_id,
782                                                   REGMASK(op->can_id),
783                                                   bcm_rx_handler, op);
784 
785                         list_del(&op->list);
786                         bcm_remove_op(op);
787                         return 1; /* done */
788                 }
789         }
790 
791         return 0; /* not found */
792 }
793 
794 /*
795  * bcm_delete_tx_op - find and remove a tx op (returns number of removed ops)
796  */
797 static int bcm_delete_tx_op(struct list_head *ops, canid_t can_id, int ifindex)
798 {
799         struct bcm_op *op, *n;
800 
801         list_for_each_entry_safe(op, n, ops, list) {
802                 if ((op->can_id == can_id) && (op->ifindex == ifindex)) {
803                         list_del(&op->list);
804                         bcm_remove_op(op);
805                         return 1; /* done */
806                 }
807         }
808 
809         return 0; /* not found */
810 }
811 
812 /*
813  * bcm_read_op - read out a bcm_op and send it to the user (for bcm_sendmsg)
814  */
815 static int bcm_read_op(struct list_head *ops, struct bcm_msg_head *msg_head,
816                        int ifindex)
817 {
818         struct bcm_op *op = bcm_find_op(ops, msg_head->can_id, ifindex);
819 
820         if (!op)
821                 return -EINVAL;
822 
823         /* put current values into msg_head */
824         msg_head->flags   = op->flags;
825         msg_head->count   = op->count;
826         msg_head->ival1   = op->ival1;
827         msg_head->ival2   = op->ival2;
828         msg_head->nframes = op->nframes;
829 
830         bcm_send_to_user(op, msg_head, op->frames, 0);
831 
832         return MHSIZ;
833 }
834 
835 /*
836  * bcm_tx_setup - create or update a bcm tx op (for bcm_sendmsg)
837  */
838 static int bcm_tx_setup(struct bcm_msg_head *msg_head, struct msghdr *msg,
839                         int ifindex, struct sock *sk)
840 {
841         struct bcm_sock *bo = bcm_sk(sk);
842         struct bcm_op *op;
843         unsigned int i;
844         int err;
845 
846         /* we need a real device to send frames */
847         if (!ifindex)
848                 return -ENODEV;
849 
850         /* check nframes boundaries - we need at least one can_frame */
851         if (msg_head->nframes < 1 || msg_head->nframes > MAX_NFRAMES)
852                 return -EINVAL;
853 
854         /* check the given can_id */
855         op = bcm_find_op(&bo->tx_ops, msg_head->can_id, ifindex);
856 
857         if (op) {
858                 /* update existing BCM operation */
859 
860                 /*
861                  * Do we need more space for the can_frames than currently
862                  * allocated? -> This is a _really_ unusual use-case and
863                  * therefore (complexity / locking) it is not supported.
864                  */
865                 if (msg_head->nframes > op->nframes)
866                         return -E2BIG;
867 
868                 /* update can_frames content */
869                 for (i = 0; i < msg_head->nframes; i++) {
870                         err = memcpy_fromiovec((u8 *)&op->frames[i],
871                                                msg->msg_iov, CFSIZ);
872 
873                         if (op->frames[i].can_dlc > 8)
874                                 err = -EINVAL;
875 
876                         if (err < 0)
877                                 return err;
878 
879                         if (msg_head->flags & TX_CP_CAN_ID) {
880                                 /* copy can_id into frame */
881                                 op->frames[i].can_id = msg_head->can_id;
882                         }
883                 }
884 
885         } else {
886                 /* insert new BCM operation for the given can_id */
887 
888                 op = kzalloc(OPSIZ, GFP_KERNEL);
889                 if (!op)
890                         return -ENOMEM;
891 
892                 op->can_id    = msg_head->can_id;
893 
894                 /* create array for can_frames and copy the data */
895                 if (msg_head->nframes > 1) {
896                         op->frames = kmalloc(msg_head->nframes * CFSIZ,
897                                              GFP_KERNEL);
898                         if (!op->frames) {
899                                 kfree(op);
900                                 return -ENOMEM;
901                         }
902                 } else
903                         op->frames = &op->sframe;
904 
905                 for (i = 0; i < msg_head->nframes; i++) {
906                         err = memcpy_fromiovec((u8 *)&op->frames[i],
907                                                msg->msg_iov, CFSIZ);
908 
909                         if (op->frames[i].can_dlc > 8)
910                                 err = -EINVAL;
911 
912                         if (err < 0) {
913                                 if (op->frames != &op->sframe)
914                                         kfree(op->frames);
915                                 kfree(op);
916                                 return err;
917                         }
918 
919                         if (msg_head->flags & TX_CP_CAN_ID) {
920                                 /* copy can_id into frame */
921                                 op->frames[i].can_id = msg_head->can_id;
922                         }
923                 }
924 
925                 /* tx_ops never compare with previous received messages */
926                 op->last_frames = NULL;
927 
928                 /* bcm_can_tx / bcm_tx_timeout_handler needs this */
929                 op->sk = sk;
930                 op->ifindex = ifindex;
931 
932                 /* initialize uninitialized (kzalloc) structure */
933                 hrtimer_init(&op->timer, CLOCK_MONOTONIC, HRTIMER_MODE_REL);
934                 op->timer.function = bcm_tx_timeout_handler;
935 
936                 /* initialize tasklet for tx countevent notification */
937                 tasklet_init(&op->tsklet, bcm_tx_timeout_tsklet,
938                              (unsigned long) op);
939 
940                 /* currently unused in tx_ops */
941                 hrtimer_init(&op->thrtimer, CLOCK_MONOTONIC, HRTIMER_MODE_REL);
942 
943                 /* add this bcm_op to the list of the tx_ops */
944                 list_add(&op->list, &bo->tx_ops);
945 
946         } /* if ((op = bcm_find_op(&bo->tx_ops, msg_head->can_id, ifindex))) */
947 
948         if (op->nframes != msg_head->nframes) {
949                 op->nframes   = msg_head->nframes;
950                 /* start multiple frame transmission with index 0 */
951                 op->currframe = 0;
952         }
953 
954         /* check flags */
955 
956         op->flags = msg_head->flags;
957 
958         if (op->flags & TX_RESET_MULTI_IDX) {
959                 /* start multiple frame transmission with index 0 */
960                 op->currframe = 0;
961         }
962 
963         if (op->flags & SETTIMER) {
964                 /* set timer values */
965                 op->count = msg_head->count;
966                 op->ival1 = msg_head->ival1;
967                 op->ival2 = msg_head->ival2;
968                 op->kt_ival1 = timeval_to_ktime(msg_head->ival1);
969                 op->kt_ival2 = timeval_to_ktime(msg_head->ival2);
970 
971                 /* disable an active timer due to zero values? */
972                 if (!op->kt_ival1.tv64 && !op->kt_ival2.tv64)
973                         hrtimer_cancel(&op->timer);
974         }
975 
976         if (op->flags & STARTTIMER) {
977                 hrtimer_cancel(&op->timer);
978                 /* spec: send can_frame when starting timer */
979                 op->flags |= TX_ANNOUNCE;
980         }
981 
982         if (op->flags & TX_ANNOUNCE) {
983                 bcm_can_tx(op);
984                 if (op->count)
985                         op->count--;
986         }
987 
988         if (op->flags & STARTTIMER)
989                 bcm_tx_start_timer(op);
990 
991         return msg_head->nframes * CFSIZ + MHSIZ;
992 }
993 
994 /*
995  * bcm_rx_setup - create or update a bcm rx op (for bcm_sendmsg)
996  */
997 static int bcm_rx_setup(struct bcm_msg_head *msg_head, struct msghdr *msg,
998                         int ifindex, struct sock *sk)
999 {
1000         struct bcm_sock *bo = bcm_sk(sk);
1001         struct bcm_op *op;
1002         int do_rx_register;
1003         int err = 0;
1004 
1005         if ((msg_head->flags & RX_FILTER_ID) || (!(msg_head->nframes))) {
1006                 /* be robust against wrong usage ... */
1007                 msg_head->flags |= RX_FILTER_ID;
1008                 /* ignore trailing garbage */
1009                 msg_head->nframes = 0;
1010         }
1011 
1012         /* the first element contains the mux-mask => MAX_NFRAMES + 1  */
1013         if (msg_head->nframes > MAX_NFRAMES + 1)
1014                 return -EINVAL;
1015 
1016         if ((msg_head->flags & RX_RTR_FRAME) &&
1017             ((msg_head->nframes != 1) ||
1018              (!(msg_head->can_id & CAN_RTR_FLAG))))
1019                 return -EINVAL;
1020 
1021         /* check the given can_id */
1022         op = bcm_find_op(&bo->rx_ops, msg_head->can_id, ifindex);
1023         if (op) {
1024                 /* update existing BCM operation */
1025 
1026                 /*
1027                  * Do we need more space for the can_frames than currently
1028                  * allocated? -> This is a _really_ unusual use-case and
1029                  * therefore (complexity / locking) it is not supported.
1030                  */
1031                 if (msg_head->nframes > op->nframes)
1032                         return -E2BIG;
1033 
1034                 if (msg_head->nframes) {
1035                         /* update can_frames content */
1036                         err = memcpy_fromiovec((u8 *)op->frames,
1037                                                msg->msg_iov,
1038                                                msg_head->nframes * CFSIZ);
1039                         if (err < 0)
1040                                 return err;
1041 
1042                         /* clear last_frames to indicate 'nothing received' */
1043                         memset(op->last_frames, 0, msg_head->nframes * CFSIZ);
1044                 }
1045 
1046                 op->nframes = msg_head->nframes;
1047 
1048                 /* Only an update -> do not call can_rx_register() */
1049                 do_rx_register = 0;
1050 
1051         } else {
1052                 /* insert new BCM operation for the given can_id */
1053                 op = kzalloc(OPSIZ, GFP_KERNEL);
1054                 if (!op)
1055                         return -ENOMEM;
1056 
1057                 op->can_id    = msg_head->can_id;
1058                 op->nframes   = msg_head->nframes;
1059 
1060                 if (msg_head->nframes > 1) {
1061                         /* create array for can_frames and copy the data */
1062                         op->frames = kmalloc(msg_head->nframes * CFSIZ,
1063                                              GFP_KERNEL);
1064                         if (!op->frames) {
1065                                 kfree(op);
1066                                 return -ENOMEM;
1067                         }
1068 
1069                         /* create and init array for received can_frames */
1070                         op->last_frames = kzalloc(msg_head->nframes * CFSIZ,
1071                                                   GFP_KERNEL);
1072                         if (!op->last_frames) {
1073                                 kfree(op->frames);
1074                                 kfree(op);
1075                                 return -ENOMEM;
1076                         }
1077 
1078                 } else {
1079                         op->frames = &op->sframe;
1080                         op->last_frames = &op->last_sframe;
1081                 }
1082 
1083                 if (msg_head->nframes) {
1084                         err = memcpy_fromiovec((u8 *)op->frames, msg->msg_iov,
1085                                                msg_head->nframes * CFSIZ);
1086                         if (err < 0) {
1087                                 if (op->frames != &op->sframe)
1088                                         kfree(op->frames);
1089                                 if (op->last_frames != &op->last_sframe)
1090                                         kfree(op->last_frames);
1091                                 kfree(op);
1092                                 return err;
1093                         }
1094                 }
1095 
1096                 /* bcm_can_tx / bcm_tx_timeout_handler needs this */
1097                 op->sk = sk;
1098                 op->ifindex = ifindex;
1099 
1100                 /* ifindex for timeout events w/o previous frame reception */
1101                 op->rx_ifindex = ifindex;
1102 
1103                 /* initialize uninitialized (kzalloc) structure */
1104                 hrtimer_init(&op->timer, CLOCK_MONOTONIC, HRTIMER_MODE_REL);
1105                 op->timer.function = bcm_rx_timeout_handler;
1106 
1107                 /* initialize tasklet for rx timeout notification */
1108                 tasklet_init(&op->tsklet, bcm_rx_timeout_tsklet,
1109                              (unsigned long) op);
1110 
1111                 hrtimer_init(&op->thrtimer, CLOCK_MONOTONIC, HRTIMER_MODE_REL);
1112                 op->thrtimer.function = bcm_rx_thr_handler;
1113 
1114                 /* initialize tasklet for rx throttle handling */
1115                 tasklet_init(&op->thrtsklet, bcm_rx_thr_tsklet,
1116                              (unsigned long) op);
1117 
1118                 /* add this bcm_op to the list of the rx_ops */
1119                 list_add(&op->list, &bo->rx_ops);
1120 
1121                 /* call can_rx_register() */
1122                 do_rx_register = 1;
1123 
1124         } /* if ((op = bcm_find_op(&bo->rx_ops, msg_head->can_id, ifindex))) */
1125 
1126         /* check flags */
1127         op->flags = msg_head->flags;
1128 
1129         if (op->flags & RX_RTR_FRAME) {
1130 
1131                 /* no timers in RTR-mode */
1132                 hrtimer_cancel(&op->thrtimer);
1133                 hrtimer_cancel(&op->timer);
1134 
1135                 /*
1136                  * funny feature in RX(!)_SETUP only for RTR-mode:
1137                  * copy can_id into frame BUT without RTR-flag to
1138                  * prevent a full-load-loopback-test ... ;-]
1139                  */
1140                 if ((op->flags & TX_CP_CAN_ID) ||
1141                     (op->frames[0].can_id == op->can_id))
1142                         op->frames[0].can_id = op->can_id & ~CAN_RTR_FLAG;
1143 
1144         } else {
1145                 if (op->flags & SETTIMER) {
1146 
1147                         /* set timer value */
1148                         op->ival1 = msg_head->ival1;
1149                         op->ival2 = msg_head->ival2;
1150                         op->kt_ival1 = timeval_to_ktime(msg_head->ival1);
1151                         op->kt_ival2 = timeval_to_ktime(msg_head->ival2);
1152 
1153                         /* disable an active timer due to zero value? */
1154                         if (!op->kt_ival1.tv64)
1155                                 hrtimer_cancel(&op->timer);
1156 
1157                         /*
1158                          * In any case cancel the throttle timer, flush
1159                          * potentially blocked msgs and reset throttle handling
1160                          */
1161                         op->kt_lastmsg = ktime_set(0, 0);
1162                         hrtimer_cancel(&op->thrtimer);
1163                         bcm_rx_thr_flush(op, 1);
1164                 }
1165 
1166                 if ((op->flags & STARTTIMER) && op->kt_ival1.tv64)
1167                         hrtimer_start(&op->timer, op->kt_ival1,
1168                                       HRTIMER_MODE_REL);
1169         }
1170 
1171         /* now we can register for can_ids, if we added a new bcm_op */
1172         if (do_rx_register) {
1173                 if (ifindex) {
1174                         struct net_device *dev;
1175 
1176                         dev = dev_get_by_index(&init_net, ifindex);
1177                         if (dev) {
1178                                 err = can_rx_register(dev, op->can_id,
1179                                                       REGMASK(op->can_id),
1180                                                       bcm_rx_handler, op,
1181                                                       "bcm", sk);
1182 
1183                                 op->rx_reg_dev = dev;
1184                                 dev_put(dev);
1185                         }
1186 
1187                 } else
1188                         err = can_rx_register(NULL, op->can_id,
1189                                               REGMASK(op->can_id),
1190                                               bcm_rx_handler, op, "bcm", sk);
1191                 if (err) {
1192                         /* this bcm rx op is broken -> remove it */
1193                         list_del(&op->list);
1194                         bcm_remove_op(op);
1195                         return err;
1196                 }
1197         }
1198 
1199         return msg_head->nframes * CFSIZ + MHSIZ;
1200 }
1201 
1202 /*
1203  * bcm_tx_send - send a single CAN frame to the CAN interface (for bcm_sendmsg)
1204  */
1205 static int bcm_tx_send(struct msghdr *msg, int ifindex, struct sock *sk)
1206 {
1207         struct sk_buff *skb;
1208         struct net_device *dev;
1209         int err;
1210 
1211         /* we need a real device to send frames */
1212         if (!ifindex)
1213                 return -ENODEV;
1214 
1215         skb = alloc_skb(CFSIZ + sizeof(struct can_skb_priv), GFP_KERNEL);
1216         if (!skb)
1217                 return -ENOMEM;
1218 
1219         can_skb_reserve(skb);
1220 
1221         err = memcpy_fromiovec(skb_put(skb, CFSIZ), msg->msg_iov, CFSIZ);
1222         if (err < 0) {
1223                 kfree_skb(skb);
1224                 return err;
1225         }
1226 
1227         dev = dev_get_by_index(&init_net, ifindex);
1228         if (!dev) {
1229                 kfree_skb(skb);
1230                 return -ENODEV;
1231         }
1232 
1233         can_skb_prv(skb)->ifindex = dev->ifindex;
1234         skb->dev = dev;
1235         can_skb_set_owner(skb, sk);
1236         err = can_send(skb, 1); /* send with loopback */
1237         dev_put(dev);
1238 
1239         if (err)
1240                 return err;
1241 
1242         return CFSIZ + MHSIZ;
1243 }
1244 
1245 /*
1246  * bcm_sendmsg - process BCM commands (opcodes) from the userspace
1247  */
1248 static int bcm_sendmsg(struct kiocb *iocb, struct socket *sock,
1249                        struct msghdr *msg, size_t size)
1250 {
1251         struct sock *sk = sock->sk;
1252         struct bcm_sock *bo = bcm_sk(sk);
1253         int ifindex = bo->ifindex; /* default ifindex for this bcm_op */
1254         struct bcm_msg_head msg_head;
1255         int ret; /* read bytes or error codes as return value */
1256 
1257         if (!bo->bound)
1258                 return -ENOTCONN;
1259 
1260         /* check for valid message length from userspace */
1261         if (size < MHSIZ || (size - MHSIZ) % CFSIZ)
1262                 return -EINVAL;
1263 
1264         /* check for alternative ifindex for this bcm_op */
1265 
1266         if (!ifindex && msg->msg_name) {
1267                 /* no bound device as default => check msg_name */
1268                 struct sockaddr_can *addr =
1269                         (struct sockaddr_can *)msg->msg_name;
1270 
1271                 if (msg->msg_namelen < sizeof(*addr))
1272                         return -EINVAL;
1273 
1274                 if (addr->can_family != AF_CAN)
1275                         return -EINVAL;
1276 
1277                 /* ifindex from sendto() */
1278                 ifindex = addr->can_ifindex;
1279 
1280                 if (ifindex) {
1281                         struct net_device *dev;
1282 
1283                         dev = dev_get_by_index(&init_net, ifindex);
1284                         if (!dev)
1285                                 return -ENODEV;
1286 
1287                         if (dev->type != ARPHRD_CAN) {
1288                                 dev_put(dev);
1289                                 return -ENODEV;
1290                         }
1291 
1292                         dev_put(dev);
1293                 }
1294         }
1295 
1296         /* read message head information */
1297 
1298         ret = memcpy_fromiovec((u8 *)&msg_head, msg->msg_iov, MHSIZ);
1299         if (ret < 0)
1300                 return ret;
1301 
1302         lock_sock(sk);
1303 
1304         switch (msg_head.opcode) {
1305 
1306         case TX_SETUP:
1307                 ret = bcm_tx_setup(&msg_head, msg, ifindex, sk);
1308                 break;
1309 
1310         case RX_SETUP:
1311                 ret = bcm_rx_setup(&msg_head, msg, ifindex, sk);
1312                 break;
1313 
1314         case TX_DELETE:
1315                 if (bcm_delete_tx_op(&bo->tx_ops, msg_head.can_id, ifindex))
1316                         ret = MHSIZ;
1317                 else
1318                         ret = -EINVAL;
1319                 break;
1320 
1321         case RX_DELETE:
1322                 if (bcm_delete_rx_op(&bo->rx_ops, msg_head.can_id, ifindex))
1323                         ret = MHSIZ;
1324                 else
1325                         ret = -EINVAL;
1326                 break;
1327 
1328         case TX_READ:
1329                 /* reuse msg_head for the reply to TX_READ */
1330                 msg_head.opcode  = TX_STATUS;
1331                 ret = bcm_read_op(&bo->tx_ops, &msg_head, ifindex);
1332                 break;
1333 
1334         case RX_READ:
1335                 /* reuse msg_head for the reply to RX_READ */
1336                 msg_head.opcode  = RX_STATUS;
1337                 ret = bcm_read_op(&bo->rx_ops, &msg_head, ifindex);
1338                 break;
1339 
1340         case TX_SEND:
1341                 /* we need exactly one can_frame behind the msg head */
1342                 if ((msg_head.nframes != 1) || (size != CFSIZ + MHSIZ))
1343                         ret = -EINVAL;
1344                 else
1345                         ret = bcm_tx_send(msg, ifindex, sk);
1346                 break;
1347 
1348         default:
1349                 ret = -EINVAL;
1350                 break;
1351         }
1352 
1353         release_sock(sk);
1354 
1355         return ret;
1356 }
1357 
1358 /*
1359  * notification handler for netdevice status changes
1360  */
1361 static int bcm_notifier(struct notifier_block *nb, unsigned long msg,
1362                         void *data)
1363 {
1364         struct net_device *dev = (struct net_device *)data;
1365         struct bcm_sock *bo = container_of(nb, struct bcm_sock, notifier);
1366         struct sock *sk = &bo->sk;
1367         struct bcm_op *op;
1368         int notify_enodev = 0;
1369 
1370         if (!net_eq(dev_net(dev), &init_net))
1371                 return NOTIFY_DONE;
1372 
1373         if (dev->type != ARPHRD_CAN)
1374                 return NOTIFY_DONE;
1375 
1376         switch (msg) {
1377 
1378         case NETDEV_UNREGISTER:
1379                 lock_sock(sk);
1380 
1381                 /* remove device specific receive entries */
1382                 list_for_each_entry(op, &bo->rx_ops, list)
1383                         if (op->rx_reg_dev == dev)
1384                                 bcm_rx_unreg(dev, op);
1385 
1386                 /* remove device reference, if this is our bound device */
1387                 if (bo->bound && bo->ifindex == dev->ifindex) {
1388                         bo->bound   = 0;
1389                         bo->ifindex = 0;
1390                         notify_enodev = 1;
1391                 }
1392 
1393                 release_sock(sk);
1394 
1395                 if (notify_enodev) {
1396                         sk->sk_err = ENODEV;
1397                         if (!sock_flag(sk, SOCK_DEAD))
1398                                 sk->sk_error_report(sk);
1399                 }
1400                 break;
1401 
1402         case NETDEV_DOWN:
1403                 if (bo->bound && bo->ifindex == dev->ifindex) {
1404                         sk->sk_err = ENETDOWN;
1405                         if (!sock_flag(sk, SOCK_DEAD))
1406                                 sk->sk_error_report(sk);
1407                 }
1408         }
1409 
1410         return NOTIFY_DONE;
1411 }
1412 
1413 /*
1414  * initial settings for all BCM sockets to be set at socket creation time
1415  */
1416 static int bcm_init(struct sock *sk)
1417 {
1418         struct bcm_sock *bo = bcm_sk(sk);
1419 
1420         bo->bound            = 0;
1421         bo->ifindex          = 0;
1422         bo->dropped_usr_msgs = 0;
1423         bo->bcm_proc_read    = NULL;
1424 
1425         INIT_LIST_HEAD(&bo->tx_ops);
1426         INIT_LIST_HEAD(&bo->rx_ops);
1427 
1428         /* set notifier */
1429         bo->notifier.notifier_call = bcm_notifier;
1430 
1431         register_netdevice_notifier(&bo->notifier);
1432 
1433         return 0;
1434 }
1435 
1436 /*
1437  * standard socket functions
1438  */
1439 static int bcm_release(struct socket *sock)
1440 {
1441         struct sock *sk = sock->sk;
1442         struct bcm_sock *bo;
1443         struct bcm_op *op, *next;
1444 
1445         if (sk == NULL)
1446                 return 0;
1447 
1448         bo = bcm_sk(sk);
1449 
1450         /* remove bcm_ops, timer, rx_unregister(), etc. */
1451 
1452         unregister_netdevice_notifier(&bo->notifier);
1453 
1454         lock_sock(sk);
1455 
1456         list_for_each_entry_safe(op, next, &bo->tx_ops, list)
1457                 bcm_remove_op(op);
1458 
1459         list_for_each_entry_safe(op, next, &bo->rx_ops, list) {
1460                 /*
1461                  * Don't care if we're bound or not (due to netdev problems)
1462                  * can_rx_unregister() is always a save thing to do here.
1463                  */
1464                 if (op->ifindex) {
1465                         /*
1466                          * Only remove subscriptions that had not
1467                          * been removed due to NETDEV_UNREGISTER
1468                          * in bcm_notifier()
1469                          */
1470                         if (op->rx_reg_dev) {
1471                                 struct net_device *dev;
1472 
1473                                 dev = dev_get_by_index(&init_net, op->ifindex);
1474                                 if (dev) {
1475                                         bcm_rx_unreg(dev, op);
1476                                         dev_put(dev);
1477                                 }
1478                         }
1479                 } else
1480                         can_rx_unregister(NULL, op->can_id,
1481                                           REGMASK(op->can_id),
1482                                           bcm_rx_handler, op);
1483 
1484                 bcm_remove_op(op);
1485         }
1486 
1487         /* remove procfs entry */
1488         if (proc_dir && bo->bcm_proc_read)
1489                 remove_proc_entry(bo->procname, proc_dir);
1490 
1491         /* remove device reference */
1492         if (bo->bound) {
1493                 bo->bound   = 0;
1494                 bo->ifindex = 0;
1495         }
1496 
1497         sock_orphan(sk);
1498         sock->sk = NULL;
1499 
1500         release_sock(sk);
1501         sock_put(sk);
1502 
1503         return 0;
1504 }
1505 
1506 static int bcm_connect(struct socket *sock, struct sockaddr *uaddr, int len,
1507                        int flags)
1508 {
1509         struct sockaddr_can *addr = (struct sockaddr_can *)uaddr;
1510         struct sock *sk = sock->sk;
1511         struct bcm_sock *bo = bcm_sk(sk);
1512         int ret = 0;
1513 
1514         if (len < sizeof(*addr))
1515                 return -EINVAL;
1516 
1517         lock_sock(sk);
1518 
1519         if (bo->bound) {
1520                 ret = -EISCONN;
1521                 goto fail;
1522         }
1523 
1524         /* bind a device to this socket */
1525         if (addr->can_ifindex) {
1526                 struct net_device *dev;
1527 
1528                 dev = dev_get_by_index(&init_net, addr->can_ifindex);
1529                 if (!dev) {
1530                         ret = -ENODEV;
1531                         goto fail;
1532                 }
1533                 if (dev->type != ARPHRD_CAN) {
1534                         dev_put(dev);
1535                         ret = -ENODEV;
1536                         goto fail;
1537                 }
1538 
1539                 bo->ifindex = dev->ifindex;
1540                 dev_put(dev);
1541 
1542         } else {
1543                 /* no interface reference for ifindex = 0 ('any' CAN device) */
1544                 bo->ifindex = 0;
1545         }
1546 
1547         if (proc_dir) {
1548                 /* unique socket address as filename */
1549                 sprintf(bo->procname, "%lu", sock_i_ino(sk));
1550                 bo->bcm_proc_read = proc_create_data(bo->procname, 0644,
1551                                                      proc_dir,
1552                                                      &bcm_proc_fops, sk);
1553                 if (!bo->bcm_proc_read) {
1554                         ret = -ENOMEM;
1555                         goto fail;
1556                 }
1557         }
1558 
1559         bo->bound = 1;
1560 
1561 fail:
1562         release_sock(sk);
1563 
1564         return ret;
1565 }
1566 
1567 static int bcm_recvmsg(struct kiocb *iocb, struct socket *sock,
1568                        struct msghdr *msg, size_t size, int flags)
1569 {
1570         struct sock *sk = sock->sk;
1571         struct sk_buff *skb;
1572         int error = 0;
1573         int noblock;
1574         int err;
1575 
1576         noblock =  flags & MSG_DONTWAIT;
1577         flags   &= ~MSG_DONTWAIT;
1578         skb = skb_recv_datagram(sk, flags, noblock, &error);
1579         if (!skb)
1580                 return error;
1581 
1582         if (skb->len < size)
1583                 size = skb->len;
1584 
1585         err = memcpy_toiovec(msg->msg_iov, skb->data, size);
1586         if (err < 0) {
1587                 skb_free_datagram(sk, skb);
1588                 return err;
1589         }
1590 
1591         sock_recv_ts_and_drops(msg, sk, skb);
1592 
1593         if (msg->msg_name) {
1594                 msg->msg_namelen = sizeof(struct sockaddr_can);
1595                 memcpy(msg->msg_name, skb->cb, msg->msg_namelen);
1596         }
1597 
1598         skb_free_datagram(sk, skb);
1599 
1600         return size;
1601 }
1602 
1603 static const struct proto_ops bcm_ops = {
1604         .family        = PF_CAN,
1605         .release       = bcm_release,
1606         .bind          = sock_no_bind,
1607         .connect       = bcm_connect,
1608         .socketpair    = sock_no_socketpair,
1609         .accept        = sock_no_accept,
1610         .getname       = sock_no_getname,
1611         .poll          = datagram_poll,
1612         .ioctl         = can_ioctl,     /* use can_ioctl() from af_can.c */
1613         .listen        = sock_no_listen,
1614         .shutdown      = sock_no_shutdown,
1615         .setsockopt    = sock_no_setsockopt,
1616         .getsockopt    = sock_no_getsockopt,
1617         .sendmsg       = bcm_sendmsg,
1618         .recvmsg       = bcm_recvmsg,
1619         .mmap          = sock_no_mmap,
1620         .sendpage      = sock_no_sendpage,
1621 };
1622 
1623 static struct proto bcm_proto __read_mostly = {
1624         .name       = "CAN_BCM",
1625         .owner      = THIS_MODULE,
1626         .obj_size   = sizeof(struct bcm_sock),
1627         .init       = bcm_init,
1628 };
1629 
1630 static const struct can_proto bcm_can_proto = {
1631         .type       = SOCK_DGRAM,
1632         .protocol   = CAN_BCM,
1633         .ops        = &bcm_ops,
1634         .prot       = &bcm_proto,
1635 };
1636 
1637 static int __init bcm_module_init(void)
1638 {
1639         int err;
1640 
1641         printk(banner);
1642 
1643         err = can_proto_register(&bcm_can_proto);
1644         if (err < 0) {
1645                 printk(KERN_ERR "can: registration of bcm protocol failed\n");
1646                 return err;
1647         }
1648 
1649         /* create /proc/net/can-bcm directory */
1650         proc_dir = proc_mkdir("can-bcm", init_net.proc_net);
1651         return 0;
1652 }
1653 
1654 static void __exit bcm_module_exit(void)
1655 {
1656         can_proto_unregister(&bcm_can_proto);
1657 
1658         if (proc_dir)
1659                 remove_proc_entry("can-bcm", init_net.proc_net);
1660 }
1661 
1662 module_init(bcm_module_init);
1663 module_exit(bcm_module_exit);
1664 

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